[VM] Adds type to Args list in FfiNative transform.

This fixes an issue during signature shaking of FfiNative calls:
`type 'ConstantExpression' is not a subtype of type 'VariableGet' of 'value'`
Which is triggered by the Arguments list having type List<VariableGet>.

TEST=ffi/ffi_native_test

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-nnbd-linux-release-x64-try
Change-Id: Iafcbca8018dab091b825277ac64a51587c929ea0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/206787
Reviewed-by: Daco Harkes <dacoharkes@google.com>
Commit-Queue: Clement Skau <cskau@google.com>
diff --git a/pkg/vm/lib/transformations/ffi_native.dart b/pkg/vm/lib/transformations/ffi_native.dart
index ec120ac..7a85d36 100644
--- a/pkg/vm/lib/transformations/ffi_native.dart
+++ b/pkg/vm/lib/transformations/ffi_native.dart
@@ -143,7 +143,7 @@
     final callFuncPtrInvocation = FunctionInvocation(
         FunctionAccessKind.FunctionType,
         StaticGet(funcPtrField),
-        Arguments(params.map((p) => VariableGet(p)).toList()),
+        Arguments(params.map<Expression>((p) => VariableGet(p)).toList()),
         functionType: dartType as FunctionType);
 
     return ReturnStatement(callFuncPtrInvocation);